There are known non-invasive living body measuring devices for measuring blood components by imaging a living body using an imaging means, and analyzing the blood vessels in the living body image (for example, refer to US2004/0162471A1). This non-invasive living body measuring device is provided with a light source, imaging part, and display part, and is mounted on the wrist of a user. This non-invasive living body measuring device illuminates a wrist containing blood vessels via a light source, and measures blood components from an image obtained by imaging the illuminated wrist, then displays the measurement result on the display part. In order to improve the accuracy of the blood component measurement, the device must positionally coincide with the measurement object blood vessel in the region to be imaged by the imaging part. The device disclosed in US2004/0162471A1 is positionally adjusted by the user while the user observes a living body image displayed on the display part of the non-invasive living body measuring device.
In the art disclosed in US2004/162471A1, the blood vessels in the living body image can not be displayed sharply, which makes it difficult for the user to determine whether or not the device is positioned in a suitable region for imaging a blood vessel.